<body>
    <div id="app">
        <p>原数据：{{msg}}</p>
        <p>新数据：{{reversedMsg}}</p>
    </div>

    <script src="https://unpkg.com/vue@3.0.11"></script>
    <script>
        Vue.createApp({
            data() {
                return {
                    msg: 'hello world!'
                }
            },
            computed: {
                reversedMsg() {
                    return this.msg.split('').reverse().join('');
                }
            }
        }).mount('#app')
    </script>
</body>